Screening carry-on and checked luggage for trace explosive residues is a common airport security practice. Sampling for trace explosive residue generally is conducted by wiping over sample surfaces, such as latches, handles, straps and zippers, with a paper or plastic detection pad that is attached to a plastic stick about one foot long. The pad picks up trace explosive particles left by fingerprints on the surfaces. The pad is then analyzed using an explosive detection system (EDS), also known as an explosive trace detector (ETD).